Processing elemental phosphorus waste at the old Solvay site eight miles west of Butte could begin as soon as next year.
The more than $18 million plant, now under construction in the Montana Connections Business Development Park off interstate 15, is the result of a nearly 20-year-long process to determine what to do with the roughly 500,000 gallons of highly flammable elemental phosphorus waste stored on the site. Belgian-based Solvay, which owns the site, and the Environmental Protection Agency agreed a couple of years ago to the concept of Solvay constructing a new plant that is expected to process the waste for the next seven or eight years. Once all the on-site hazardous phosphorus has been put through the furnace, the company will accept elemental phosphorus waste from outside sources and keep operating.
Dan Bersanti, Solvay site manager, said the company doesn’t have customers for that waste processing yet. But he said there is no worry about the future.
“There’ll be customers,” Bersanti said.
Elemental phosphorus is used to make a variety of products, including baking soda. Butte’s former phosphorus plant primarily produced phosphates for laundry detergent, Bersanti said previously.
But elemental phosphorous, when in contact with air, is highly flammable. It burns so hot that the United Nations banned its use for munitions against civilians in the 1980s.
Construction on the new plant, which began in April, is well under way. Workers have laid down a foundation and erected a steel frame. A ramp is being built to run between the buried concrete tank that holds the elemental phosphorous waste, and the plant. Not far from the plant, workers are in the middle of assembling a water tank that will be roughly 12 feet tall and will hold 180,000 gallons of water in the event of an emergency. Bersanti said there will also be fire hydrants for the fire department around the site and a sprinkler system will be inside the building.
The furnace that will be added will burn as hot as 1,110 degrees Fahrenheit.
The phosphorus waste has long been held under water in the mostly buried concrete tank on the site since 1997 when the plant shut down. Though the site has gone through many previous owners since the 1950s, the company that held it the longest was Stauffer Chemical Company.
A 2015 study Solvay commissioned stated that the cleanup plan runs a high risk for serious worker injury and a medium risk for worker fatality from both fire and phosphine gas for the duration of the sludge cleanup. The gas will be a byproduct of the waste processing.
Once the plant is ready to operate, Solvay will hire about eight new workers to handle the toxic material and the plant will operate on a 24-7 basis, Bersanti said.
After it is up and running, a worker, using an excavator, will dig into the wet phosphorous waste in the concrete tank and transfer that material into a container that is already holding water. The sludge-and-water filled container will then be transported into the plant, where it will be heated up inside the industrial furnace. The phosphorus waste will condense into a liquid.
The liquid phosphorus will then be put on a specially equipped rail car that is designed to continue to keep the material wet. The rail car will be pressurized with nitrogen to act as a blanket to take out whatever air is in the top of the rail car to make sure the material is inert. The rail car will leave the Port of Montana about once a month, Bersanti said.
Bersanti said the company isn’t sure yet who will take the transformed material, but he said it could wind up being shipped to either Canada or to other parts of the U.S.
“Phosphorus is transported all the time,” Bersanti said. “This is not a new hazard.”
Other, new waste created from processing the old waste will be permanently stored in the basements of the hollowed-out concrete silos, which are vestiges of the site's once-active industrial past. The row of silos are a short distance to the east of the new plant. The basements are lined in concrete.
What will happen to the more than five million tons of slag dunes and the tailings located on the west side of the site is still an open question, Bersanti said. A remedial plan for that still has to go through a public process and get approval from the EPA.
But, Bersanti said there aren’t many options besides burying the radioactive slag, waste from the approximately 50 years of processing elemental phosphorus, and capping it. The tailings, waste from the dust collected when the phosphorus was being processed, will also likely be buried over and capped, Bersanti said.
Bersanti said the slag might contain trace amounts of phosphorus, but the tailings have none.
The Space Propulsion Group, which has been testing experimental hybrid fuel rockets at the Solvay site since 2009, is still operating. But the company moved into the midst of the moonscape of slag dunes to be out of the way of the plant’s construction, Bersanti said.
Another aspect of the site that is moving forward is Butte-Silver Bow County’s plan to build a rail line between the Port of Montana and a parcel that will enable Montana Craft Malt and Western States Asphalt to grow their businesses, said Kristen Rosa, the county’s TIFID administrator. If the rail line goes through, it will be built on about 30 acres of Solvay's land to the east of the new plant.
Rosa will be making a presentation before the Council of Commissioners Wednesday evening to discuss the operating agreement the county is trying to put into place for that project.
If all goes well, Rosa said the rail line will be built next year and be operable by the fall of 2020.